1. Field of the Invention
The present invention relates to a damper assembly for a starting clutch in an automatic transmission and a damper assembly for a lock-up clutch.
2. Related Background Art
In the past, a damper assembly comprising a plurality of springs, in which an input member and an output member are elastically interconnected via springs in a rotational direction, has been used for absorbing abrupt fluctuation in torque to be inputted.
As such a damper assembly, for example, a damper assembly as disclosed in Japanese Patent Application Laid-Open No. 8-338475 has been developed. FIG. 7 is a sectional view of a lock-up clutch 101 in which a damper assembly 127 is incorporated.
In the damper assembly, a plurality of spring holding portions 115, 121 are provided in an input member (piston plate 109, friction material 113, hold plate 114) and an output member (driven plate 110), respectively, in a circumferential direction, and a plurality of springs 111 are held in the spring holding portions in series, so that the input and output members are elastically interconnected in a rotational direction and the springs 111 held in series are interconnected via an intermediate member 123 rotatable relative to the input and output members.
Further, the intermediate member 123 is constituted by a cylindrical connecting portion 124 rotatably housed in a gap d (refer to FIG. 8) between an outer periphery of the hold plate 114 and an inner periphery of a cylindrical portion 112 of the piston plate 109, and a plurality (four) of pawls 125 bent radially inwardly in a substantially L-shape at one side of the connecting portion 124.
Each of the pawls 125 of the intermediate member 123 has a tapered tip end and is inserted between the springs 111 held in the spring holding portions 115, 121 so that, when the input and output members are rotated relative to each other, the springs 111 are operated in series without deforming the springs in a curved form as less as possible. On the other hand, the connecting portion 124 of the intermediate member 123 serves to interconnect all of the pawls 125 in an annular fashion so that, when the input and output members are rotated relative to each other, all of the pawls 125 are synchronized to operate the springs 111 held in the spring holding portions 115, 121 in series, similarly.
With an arrangement as mentioned above, when the piston plate 109 is advanced by control oil pressure acting on a back side of the piston plate 109, the friction material 113 on a front side of the piston plate 109 is engaged by an inner surface 102a of a converter cover 102, with the result that the converter cover 102 and a turbine 104, i.e., a pump 103 and the turbine 104 are directly interconnected mechanically through the lock-up clutch 101, thereby establishing a lock-up condition. In this condition, the torque inputted to the piston plate 109 of the lock-up clutch 101 is transmitted, through the plurality of springs 111, to the driven plate 110 and then to the turbine 104. In this case, the pair of springs 111 housed in the corresponding spring holding portions 115, 121 of the hold plate 114 and the driven plate 110 act in series via the intermediate member 123 to absorb the transmitted torque with the total length of both springs 111.
However, in the above-mentioned conventional damper assembly, during the operation, if excessive load is received from the engine, the springs of the damper assembly may be closely contacted (i.e., over compressed) to damage the springs. Further, if spring constants of two springs arranged in series are different, the springs having smaller spring constant may be closely contacted firstly to damage them.
Furthermore, in the conventional damper assembly, since the connecting member is disposed in the cylindrical gap between the outer periphery of the hold plate 114 and the cylindrical portion of the piston plate 109, outer diameters of the springs to be inserted are limited or the entire dimension of the damper assembly becomes bulky.
Therefore, an object of the present invention is to provide a damper assembly in which springs of the damper assembly are prevented from being closely contacted to prevent damage of the springs even if excessively load is received from an engine during the operation of the damper assembly.
Another object of the present invention is to provide a damper assembly in which, even when spring constants of two springs arranged in series are changed, the springs having smaller spring constant are prevented from being closely contacted to prevent damage of such springs.
A further object of the present invention is to make the entire damper assembly compact.
To achieve the above objects, according to the present invention, there is provided a damper assembly comprising a retainer plate and a driven plate, and wherein springs are held in series through an intermediate member, and a relative angle between the retainer plate and the intermediate member is regulated by engaging a first projection provided on the intermediate member with a containing portion provided in the retainer plate, and a relative angle between the retainer plate and the driven plate is regulated by engaging a second projection provided on the retainer plate with an abutment portion provided on the driven plate.
With this arrangement, the first projection provided on the intermediate member is regulated by the containing portion of the retainer plate, and, further, the abutment portion provided on the driven plate is received by the second projection of the retainer plate, so that the relative angles of the intermediate member and the driven plate with respect to the retainer plate can be regulated.
Since the connecting portion of the intermediate member is disposed inwardly of the springs, an outer diameter of the damper assembly is not changed. Thus, the damper assembly can be made more compact.